Re: [hatari-devel] Pure debugger, illegal opcodes, exceptions

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On tiistai 09 lokakuu 2012, Uwe Seimet wrote:
> > Again, With moonspeeder, it's the Illegal.l (seen in the traces) that
> > generates the PC jumps to $10
> > (Maybe it's not related to the bug you've found, but it seems at first
> > glance)
> > 
> > Maybe a closer look to this instruction would help.
> 
> I just checked it on a real TT: PD modifies all (or almost all)
> exception vectors. Does moonspeeder also modify these vectors?

As PD works even with WinUAE core when using TOS v1.04 (but not TOS v1.62
which still implies 68000 i.e. similar CPU exception frames), do you know
whether there is some difference in how that handles exceptions compared to
newer TOS versions?

Interestingly even the output with TOS vv1.04 differs between
Hatari versions.  With WinUAE core:
	Autostart file 'DESKTOP.INF' for 'PD.PRG' matched.
	Autostart file removed.
	Exception 2 (0) at fc0ee4 -> fc0ee6!
	Exception 2 (0) at 2cd76 -> 2cd86!

Whereas with old UAE core:
	Autostart file 'DESKTOP.INF' for 'PD.PRG' matched.
	Autostart file removed.
	Bus Error at address $fffa42, PC=$2cd76

I.e. there was no bus error at fc0ee4.  According to Compedium:
	"On pre-TOS v2.00, this location marked the beginning of
     the operating system ROMs."


	- Eero